Isabel Myers used this answer sheet card in her research during the early stages of developing the famous Myers-Briggs Type Indicator personality test. She created the test during World War II to find the right jobs for women who had no work experience outside the home.

Katharine Briggs, left, and daughter Isabel Myers, shown in 1923, created the Myers-Briggs Type Indicator personality test, which is now given to roughly 2 million people a year.

Katharine Downing Myers is the daughter-in-law of Isabel Myers, one of the two women who created the hugely popular Myers-Briggs Type Indicator. She helped Isabel Myers with her personality research project and eventually married Isabel's son, Peter. The two are divorced but still close and are the two last living copyright holders of the test.

Some grandmothers pass down cameo necklaces. Katharine Cook Briggs passed down the world’s most widely used personality test.

Chances are you’ve taken the Myers-Briggs Type Indicator, or will. Roughly 2 million people a year do. It has become the gold standard of psychological assessments, used in businesses, government agencies and educational institutions. Along the way, it has spawned a multimillion-dollar business around its simple concept that everyone fits one of 16 personality types.

Now, 50 years after the first time anyone paid money for the test, the Myers-Briggs legacy is reaching the end of the family line. The youngest heirs don’t want it. And it’s not clear whether organizations should, either.

That’s not to say it hasn’t had a major influence.

More than 10,000 companies, 2,500 colleges and universities and 200 government agencies in the United States use the test. From the State Department to McKinsey & Co., it’s a rite of passage. It’s estimated that 50 million people have taken the Myers-Briggs personality test since the Educational Testing Service first added the research to its portfolio in 1962.

The test, whose first research guinea pigs were George Washington University students, has seen financial success commensurate to this cultlike devotion among its practitioners. CPP, the private company that publishes Myers-Briggs, brings in roughly $20 million a year from it and the 800 other products, such as coaching guides, that it has spawned.

Yet despite its widespread use and vast financial success, and although it was derived from the work of Carl Jung, one of the most famous psychologists of the 20th century, the test is highly questioned by the scientific community.

To begin even before its arrival in Washington: Myers-Briggs traces its history to 1921, when Jung, a Swiss psychiatrist, published his theory of personality types in the book “Psychologische Typen.” Jung had become well known for his pioneering work in psychoanalysis and close collaboration with Sigmund Freud, though by the 1920s the two had severed ties.

Psychoanalysis was a young field and one many regarded skeptically. Still, it had made its way across the Atlantic not only to the university offices of scientists but also to the home of a mother in Washington.

Katharine Cook Briggs was a voracious reader of the new psychology books coming out in Europe, and she shared her fascination with Jung’s latest work — in which he developed the concepts of introversion and extroversion — with her daughter, Isabel Myers. They would later use Jung’s work as a basis for their own theory, which would become the Myers-Briggs Type Indicator. MBTI is their framework for classifying personality types along four distinct axes: introversion vs. extroversion, sensing vs. intuition, thinking vs. feeling and judging vs. perceiving. A person, according to their hypothesis, has one dominant preference in each of the four pairs. For example, he might be introverted, a sensor, a thinker and a perceiver. Or, in Myers-Briggs shorthand, an “ISTP.”

Everyone, they posited, fits one of the 16 possible combinations.

Today, organizations administer the personality test to employees, then use the results as a basis for training programs. The basic idea is that knowing your personality type, and those of others, will help you interact more effectively with colleagues and identify your strengths.

The testing process seems simple enough: a multiple-choice questionnaire, with a discussion afterward about what your personality type says about you. And yet behind it lies the elaborate business model and enormous marketing push that have enthroned MBTI in the pantheon of human resources programs.

Corporate America has its own religions, and one of them is Myers-Briggs.

It was World War II, and Isabel Myers was thinking about peace.

War and peace, in fact, are what the family would come to describe as the true cause and effect of developing the Myers-Briggs indicator. World War II created a need for women to fill professional jobs on the home front. Isabel Myers saw an opportunity to use personality testing as a way to identify women’s job proclivities on the basis of innate character traits rather than prior professional experience, which many women did not have at the time.

“What Isabel decided was, if she could give people access to knowing their psychological type, it would be a contribution to world peace,” says Katharine Myers, the daughter-in-law of Isabel Myers.

So Isabel had her mission. Soon her home filled with index cards mapping out her theory. Lots of index cards.

Isabel by that time was married, a mother herself and tending a home in Swarthmore, Pa. She found a helper for her project in Katharine Downing, now Myers, whom she paid to help her hand-copy personality types onto 5-by-8-inch cards. The young girl went to school with Isabel’s son Peter, an Eagle Scout.

“In eighth grade, I got a Valentine in Morse code,” Katharine recalls. It’s one of her earliest memories of Peter, and the Myers family she would one day marry into. “And that was really the beginning of the rest of our lives.”

At 86 years old, Katharine and Peter are the last living copyright holders of his mother’s and grandmother’s legacy. CPP, however, is the exclusive publisher of the test.

“The folklore is that when it started it made about a thousand dollars,” says Jeffrey Hayes, chief executive of CPP. He won’t say precisely how much it makes today. Just “millions,” as he put it.

The number is more like $20 million in revenue a year.

The framework itself has barely changed since Katharine Cook Myers and Isabel Briggs created it decades ago, but in the meantime CPP has developed nearly 800 products related to the assessment — guides to interpreting your results, guides for coaching others on interpreting their results, guides for enhancing team-building based on everyone’s results.

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